package inventory

import (
	"context"
	"strings"
	"testing"
)

// What each machine did with what it was last sent.
//
// Until this, a refusal or a failure moved last_seen and the reason went to a log line — so
// "which machine is not doing what it was told" had no answer the next morning, which is the
// question a mesh exists to answer.

func nodeNamed(t *testing.T, inv *Inventory, name string) string {
	t.Helper()
	n, err := inv.AddNode(context.Background(), name)
	if err != nil {
		t.Fatal(err)
	}
	return n.ID
}

func TestRefusedAndFailedAreDifferentSituations(t *testing.T) {
	// Refused means the machine is exactly as it was, and what is wrong is in what was sent.
	// Failed means it is in a state nobody declared, and what is wrong is on the machine. One
	// word for both would make the report say less than the node did.
	inv := fresh(t)
	ctx := context.Background()
	refuser := nodeNamed(t, inv, "refuser")
	failer := nodeNamed(t, inv, "failer")

	if _, err := inv.RecordDoing(ctx, refuser, Doing{
		Outcome: OutcomeRefused, Refused: "resource \"x\": a file needs a path",
	}); err != nil {
		t.Fatal(err)
	}
	if _, err := inv.RecordDoing(ctx, failer, Doing{
		Outcome: OutcomeFailed,
		Failed:  []FailedResource{{ID: "svc", Error: "unit not found"}},
		Applied: 4,
	}); err != nil {
		t.Fatal(err)
	}

	wrong, err := inv.NotDoingWhatTheyWereTold(ctx)
	if err != nil {
		t.Fatal(err)
	}
	if len(wrong) != 2 {
		t.Fatalf("got %d", len(wrong))
	}
	by := map[string]Doing{}
	for _, d := range wrong {
		by[d.Node] = d
	}
	if by["refuser"].Outcome != OutcomeRefused || !strings.Contains(by["refuser"].Refused, "needs a path") {
		t.Fatalf("got %+v", by["refuser"])
	}
	if by["failer"].Outcome != OutcomeFailed || len(by["failer"].Failed) != 1 {
		t.Fatalf("got %+v", by["failer"])
	}
	// And how much DID work, because "four of five" and "none of five" are different machines.
	if by["failer"].Applied != 4 {
		t.Fatalf("what did apply was not kept: %+v", by["failer"])
	}
}

func TestAMachineDoingWhatItWasToldIsNotOnTheList(t *testing.T) {
	inv := fresh(t)
	ctx := context.Background()
	id := nodeNamed(t, inv, "fine")
	if _, err := inv.RecordDoing(ctx, id, Doing{Outcome: OutcomeApplied, Applied: 6}); err != nil {
		t.Fatal(err)
	}
	wrong, err := inv.NotDoingWhatTheyWereTold(ctx)
	if err != nil {
		t.Fatal(err)
	}
	if len(wrong) != 0 {
		t.Fatalf("a machine that did as it was told is listed as wrong: %+v", wrong)
	}
	// It is still answerable about, which is a different question.
	d, said, err := inv.DoingOf(ctx, "fine")
	if err != nil || !said {
		t.Fatalf("said=%v err=%v", said, err)
	}
	if d.Wrong() || d.Applied != 6 {
		t.Fatalf("got %+v", d)
	}
}

func TestTheLastReportReplacesTheOneBefore(t *testing.T) {
	// The question is the machine's CURRENT state. "This failed an hour ago and then succeeded"
	// is not a machine anybody needs to look at, and a table of every report would bury the ones
	// that matter under the ones that do not.
	inv := fresh(t)
	ctx := context.Background()
	id := nodeNamed(t, inv, "recovered")
	if _, err := inv.RecordDoing(ctx, id, Doing{
		Outcome: OutcomeFailed, Failed: []FailedResource{{ID: "a", Error: "no"}},
	}); err != nil {
		t.Fatal(err)
	}
	if _, err := inv.RecordDoing(ctx, id, Doing{Outcome: OutcomeApplied, Applied: 3}); err != nil {
		t.Fatal(err)
	}
	wrong, err := inv.NotDoingWhatTheyWereTold(ctx)
	if err != nil {
		t.Fatal(err)
	}
	if len(wrong) != 0 {
		t.Fatalf("a machine that recovered is still listed as wrong: %+v", wrong)
	}
	d, _, _ := inv.DoingOf(ctx, "recovered")
	if len(d.Failed) != 0 {
		t.Fatalf("the old failure survived: %+v", d)
	}
}

func TestAMachineThatHasSaidNothingIsNotWrong(t *testing.T) {
	// It may be new, switched off, or unreachable. None of those is a machine that tried and
	// could not, and treating silence as failure would have somebody debug a machine that has
	// simply never been sent anything.
	inv := fresh(t)
	ctx := context.Background()
	nodeNamed(t, inv, "silent")
	wrong, err := inv.NotDoingWhatTheyWereTold(ctx)
	if err != nil {
		t.Fatal(err)
	}
	if len(wrong) != 0 {
		t.Fatalf("silence was read as failure: %+v", wrong)
	}
	if _, said, err := inv.DoingOf(ctx, "silent"); err != nil || said {
		t.Fatalf("a machine that never reported was reported about: said=%v err=%v", said, err)
	}
}

func TestWhatANodeSaidGoesWhenTheNodeDoes(t *testing.T) {
	inv := fresh(t)
	ctx := context.Background()
	id := nodeNamed(t, inv, "leaving")
	if _, err := inv.RecordDoing(ctx, id, Doing{Outcome: OutcomeFailed}); err != nil {
		t.Fatal(err)
	}
	if _, err := inv.store.Pool().Exec(ctx, `delete from node where name = 'leaving'`); err != nil {
		t.Fatal(err)
	}
	var left int
	if err := inv.store.Pool().QueryRow(ctx, `select count(*) from node_report`).Scan(&left); err != nil {
		t.Fatal(err)
	}
	if left != 0 {
		t.Fatalf("%d report(s) outlived the machine", left)
	}
}

// "Behind" must mean not running what the mesh would send, not only "failed".
//
// novox/hq ADR 0010 names losing "did my change go out?" as the real risk of replacing a pipeline
// with a comparison. With behind meaning only failed-or-refused, that question was answerable
// exactly for the machines that broke — and for every machine that worked, the answer was silence
// whether the change had gone out or not.
func TestAMachineIsWaitingWhenWhatItWasSentIsNotWhatItShouldBe(t *testing.T) {
	inv := ForTest(t)
	ctx := t.Context()
	anchor, err := inv.AddNode(ctx, "anchor")
	if err != nil {
		t.Fatal(err)
	}
	if _, err := inv.AddNode(ctx, "laptop"); err != nil {
		t.Fatal(err)
	}

	// Never sent anything: waiting, and said differently. Nobody has ever asked it to be
	// anything, which is not the same as it being out of date.
	waiting, err := inv.Waiting(ctx, map[string]string{"anchor": "aaa", "laptop": "bbb"})
	if err != nil {
		t.Fatal(err)
	}
	if len(waiting) != 2 {
		t.Fatalf("machines that were never sent anything are not waiting: %+v", waiting)
	}
	for _, m := range waiting {
		if !m.Never {
			t.Fatalf("%s was never sent anything and does not say so: %+v", m.Node, m)
		}
	}

	// Sent what it should be: not waiting.
	if err := inv.RecordSent(ctx, anchor.ID, "aaa"); err != nil {
		t.Fatal(err)
	}
	waiting, err = inv.Waiting(ctx, map[string]string{"anchor": "aaa", "laptop": "bbb"})
	if err != nil {
		t.Fatal(err)
	}
	if len(waiting) != 1 || waiting[0].Node != "laptop" {
		t.Fatalf("a machine sent exactly what it should be is still waiting: %+v", waiting)
	}

	// The declaration changes: waiting again, and no longer "never".
	waiting, err = inv.Waiting(ctx, map[string]string{"anchor": "ccc", "laptop": "bbb"})
	if err != nil {
		t.Fatal(err)
	}
	var found bool
	for _, m := range waiting {
		if m.Node != "anchor" {
			continue
		}
		found = true
		if m.Never {
			t.Fatal("a machine that has been sent something is reported as never told")
		}
		if m.Sent != "aaa" {
			t.Fatalf("what it was last sent was lost: %+v", m)
		}
	}
	if !found {
		t.Fatal("a machine whose declaration changed since it was sent is not waiting")
	}
}

// A machine nobody worked out is not reported as waiting: saying so would invent a comparison.
func TestAMachineWithNothingComputedForItIsNotWaiting(t *testing.T) {
	inv := ForTest(t)
	ctx := t.Context()
	node, err := inv.AddNode(ctx, "unresolvable")
	if err != nil {
		t.Fatal(err)
	}
	// It has been sent something before, which is what makes this the case the guard is for: a
	// machine with a digest and nothing computed for it would compare against the empty string
	// and look out of date, when the truth is that nobody worked out what it should be.
	if err := inv.RecordSent(ctx, node.ID, "what-it-got-last-time"); err != nil {
		t.Fatal(err)
	}
	waiting, err := inv.Waiting(ctx, map[string]string{})
	if err != nil {
		t.Fatal(err)
	}
	if len(waiting) != 0 {
		t.Fatalf("a machine the caller could not work out was reported as waiting: %+v", waiting)
	}
}

// **A failure that repeats is told apart from one that just happened.** A node re-applies on a
// steady interval and reports each time, so a resource that will never apply arrives as the same
// report over and over — one row, replaced, "failed" at a fresh time — and nothing distinguished
// it from a failure that goes away by itself (novox/hq 04-ISSUES/065). The row now keeps when the
// current failure began and how many reports in a row have said it.
func TestTheSameFailureReportedAgainIsCountedNotRestarted(t *testing.T) {
	inv := fresh(t)
	ctx := context.Background()
	id := nodeNamed(t, inv, "looping")
	same := Doing{Outcome: OutcomeFailed, Failed: []FailedResource{{ID: "img", Error: "no such image"}}}

	if _, err := inv.RecordDoing(ctx, id, same); err != nil {
		t.Fatal(err)
	}
	first, _, err := inv.DoingOf(ctx, "looping")
	if err != nil {
		t.Fatal(err)
	}
	if first.Times != 1 || first.Since == nil || first.Stuck() {
		t.Fatalf("one failure is one failure, not yet stuck: %+v", first)
	}

	for range StuckAfter - 1 {
		if _, err := inv.RecordDoing(ctx, id, same); err != nil {
			t.Fatal(err)
		}
	}
	again, _, err := inv.DoingOf(ctx, "looping")
	if err != nil {
		t.Fatal(err)
	}
	if again.Times != StuckAfter || !again.Stuck() {
		t.Fatalf("the same failure %d times is stuck: %+v", StuckAfter, again)
	}
	if !again.Since.Equal(*first.Since) {
		t.Fatalf("the failure began at %s and the row now says %s", *first.Since, *again.Since)
	}

	// The same resource failing with different words — a duration, a counter — is still the same
	// failure: it is the resource that loops, not the sentence.
	reworded := Doing{Outcome: OutcomeFailed, Failed: []FailedResource{{ID: "img", Error: "no such image (after 31s)"}}}
	if _, err := inv.RecordDoing(ctx, id, reworded); err != nil {
		t.Fatal(err)
	}
	still, _, err := inv.DoingOf(ctx, "looping")
	if err != nil {
		t.Fatal(err)
	}
	if still.Times != StuckAfter+1 || !still.Stuck() {
		t.Fatalf("the same resource failing in other words restarted the count: %+v", still)
	}

	// A different failure is a new situation, not a longer one.
	other := Doing{Outcome: OutcomeFailed, Failed: []FailedResource{{ID: "svc", Error: "unit not found"}}}
	if _, err := inv.RecordDoing(ctx, id, other); err != nil {
		t.Fatal(err)
	}
	changed, _, err := inv.DoingOf(ctx, "looping")
	if err != nil {
		t.Fatal(err)
	}
	if changed.Times != 1 || changed.Stuck() || !changed.Since.After(*first.Since) && !changed.Since.Equal(*first.Since) {
		t.Fatalf("a new failure starts the count again: %+v", changed)
	}

	// And a clean apply clears it: the machine is doing what it was told, since nothing.
	if _, err := inv.RecordDoing(ctx, id, Doing{Outcome: OutcomeApplied, Applied: 2}); err != nil {
		t.Fatal(err)
	}
	fine, _, err := inv.DoingOf(ctx, "looping")
	if err != nil {
		t.Fatal(err)
	}
	if fine.Times != 0 || fine.Since != nil || fine.Stuck() {
		t.Fatalf("a machine doing what it was told is not stuck: %+v", fine)
	}

	// The list of what is wrong carries the count, so `status` can say it.
	if _, err := inv.RecordDoing(ctx, id, same); err != nil {
		t.Fatal(err)
	}
	wrong, err := inv.NotDoingWhatTheyWereTold(ctx)
	if err != nil {
		t.Fatal(err)
	}
	if len(wrong) != 1 || wrong[0].Times != 1 || wrong[0].Since == nil {
		t.Fatalf("got %+v", wrong)
	}
}